Structure of a SusD homologue, BT1043, involved in mucin O-glycan utilization in a prominent human gut symbiont.
Structure of a SusD homologue, BT1043, involved in mucin O-glycan utilization in a prominent human gut symbiont.
复制标题
SUSD同源物的结构BT1043，参与巨大的人类肠道共生体中粘蛋白O-聚糖利用率。
DOI：
10.1021/bi801942a
复制
发表时间：
2009-02-24
期刊：
影响因子：
2.9
通讯作者：
Smith, Thomas J.
中科院分区：
文献类型：
--
作者：
Koropatkin, Nicole;Martens, Eric C.;Gordon, Jeffrey I.;Smith, Thomas J.
哺乳动物远端肠道细菌具有扩大的利用聚糖的能力。在缺乏膳食来源的情况下，一些种属依赖于宿主来源的粘膜聚糖。多形拟杆菌是一种重要的人类肠道共生体，其觅食宿主聚糖的能力有助于其在个体宿主中持续存在的能力以及在出生时自然传播到新宿主的能力。该物种识别宿主聚糖的分子基础尚不清楚，但可能是通过作为B之间主要界面的一套扩展的外膜聚糖结合蛋白发生的。微生物学及其环境。这里给出的是B的原子结构。多形微粒蛋白BT 1043，一种参与宿主聚糖代谢的外膜脂蛋白。尽管缺乏可检测的氨基酸序列相似性，但BT 1043是B的结构同源物。多形淀粉结合蛋白SusD.这两种结构都由四方肽重复序列主导，这可能有助于与聚糖摄取所需的外膜β-桶转运蛋白结合。与N-乙酰基乳糖胺复合的BT 1043的结构揭示了通过与β-N-乙酰基葡糖胺的还原末端的氢键相互作用介导的识别，表明在结合从粘蛋白多肽释放的聚糖中的作用。这与靶向粘蛋白聚糖的末端非还原半乳糖残基的CBM 32家族成员形成对比。BT 1043的高度铰接的聚糖结合口袋表明，与先前观察到的SusD相比，与BT 1043的配体结合更多地依赖于与复合糖残基的相互作用。氨基酸序列水平的多样性可能反映了来自共同祖先的早期分歧，而SusD家族独特且保守的α-螺旋折叠表明在聚糖摄取中具有相似的功能。
Mammalian distal gut bacteria have an expanded capacity to utilize glycans. In the absence of dietary sources, some species rely on host-derived mucosal glycans. The ability of Bacteroides thetaiotaomicron, a prominent human gut symbiont, to forage host glycans contributes to both its ability to persist within an individual host and to be transmitted naturally to new hosts at birth. The molecular basis of host glycan recognition by this species is still unknown, but likely occurs through an expanded suite of outermembrane glycan-binding proteins that are the primary interface between B. thetaiotaomicron and its environment. Presented here is the atomic structure of the B. thetaiotaomicron protein BT1043, an outermembrane lipoprotein involved in host glycan metabolism. Despite a lack of detectable amino acid sequence similarity, BT1043 is a structural homolog of the B. thetaiotaomicron starch-binding protein SusD. Both structures are dominated by tetratrico peptide repeats that may facilitate association with outer membrane β-barrel transporters required for glycan uptake. The structure of BT1043 complexed with N-acetyl lactosamine reveals that recognition in mediated via hydrogen-bonding interactions with the reducing end of β-N-acetyl glucosamine, suggesting a role in binding glycans liberated from the mucin polypeptide. This is in contrast to CBM 32 family members that target the terminal non-reducing galactose residue of mucin glycans. The highly articulated glycan-binding pocket of BT1043 suggests that ligand binding to BT1043 relies more upon interactions with the composite sugar residues than upon overall ligand conformation as previously observed for SusD. The diversity in amino acid sequence level likely reflects early divergence from a common ancestor while the unique and conserved α-helical fold the SusD family suggests a similar function in glycan uptake.
登录
查看更多内容
影响因子：
2.9
作者：
Boraston, Alisdair B.;Ficko-Blean, Elizabeth;HealeyT, Michael
通讯作者：
HealeyT, Michael
影响因子：
30.3
作者：
Martens EC;Chiang HC;Gordon JI
通讯作者：
Gordon JI
影响因子：
4.8
作者：
Ficko-Blean, Elizabeth;Boraston, Alisdair B.
通讯作者：
Boraston, Alisdair B.
DOI：
10.1107/s0907444998003254
发表时间：
1998-09-01
期刊：
ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY
影响因子：
--
作者：
Brunger, AT;Adams, PD;Warren, GL
通讯作者：
Warren, GL
影响因子：
3
作者：
NICHOLLS, A;HONIG, B
通讯作者：
HONIG, B